This addon is a companion piece to the article about Odoo JavaScript 101 - Part 2: Creating an OWL View from scratch.
This tutorial companion is made for Odoo version 14 but doesn't work well on very old Odoo 14 repository (before February 10).
The OWL library inside your project should be >= 1.2.4, you can check that by opening the browser console and typing:
owl.__info__
The output should be:
{version: '1.2.4', date: '2021-02-10T13:24:25.187Z', hash: '985e985', url: 'https://github.com/odoo/owl'}